Synthesis, crystal structure, spectroscopy and electroluminescence of zinc(II) complexes containing bidentate 2-(2-pyridyl)quinoline derivative ligands

Three bidentate ligands, 4-phenyl-2-(2-pyridyl)-quinoline (ppq), 6-(carbazol-9-yl)-4-phenyl-2-(2-pyridyl)-quinoline (cpq) and 6-diphenylamino-4-phenyl-2-(2-pyridyl)-quinoline (dpq) and their zinc(II) complexes, have been designed and synthesized. The crystal structure of [Zn(ppq)(2)Cl]PF6 shows that the central zinc atom is coordinated with one chloride and four nitrogen atoms from two ligands. The introduction of an electron-donating substituent such as carbazole or an aromatic amine group at the 6-position of the quinoline moiety can generate colored tunable Zn complexes, and the photoluminescence (PL) wavelength was modulated from 418 nm for [Zn(ppq)(2)Cl]PF6 to 591 nm for [Zn(cpq)(2)Cl]PF6 and 638 nm for [Zn(dpq)(2)Cl]PF6 in CH2Cl2 solution. The electroluminescence spectrum of [Zn(dpq)(2)Cl]PF6 exhibits pure red light emission with the Commission Internationale de L'Eclairage (CIE) coordinates (0.63, 0.36) and a maximum at 648 nm.

Tetraaqua(1,10-phenanthroline-kappa(2) N, N ')copper(II)naphthalene-1,5-disulfonate dihydrate

In the title structure, [Cu(C12H8N2)(H2O)(4)](C10H6S2O6)center dot-2H(2)O, the cation lies on a crystallographic twofold rotation axis and the anion lies on a centre of inversion. The Cu-II atom is coordinated by two N atoms of a 1,10-phenanthroline ligand and four O atoms from four water ligands in a distorted octahedral geometry. The unique Cu-O distances are 2.054 (2) and 2.088 (2) angstrom and the Cu-N distance is 2.073 (2) angstrom. In the crystal structure, a three-dimensional supramolecular framework is constructed by extensive intermolecular O-H center dot center dot center dot O hydrogen bonds.

New neutral nickel(II) complexes bearing pyrrole-imine chelate ligands: synthesis, structure and norbornene polymerization behavior

New neutral nickel(II) complexes bearing nonsymmetric bidentate pyrrole-imine chelate ligands (4a-d), [2-(ArNCH)C4H3N]Ni(PPh3)Ph [Ar=2,6-diisopropylphenyl (a), 2-methyl-6-isopropylphenyl (b), 2,6-diethylphenyl (c), 2-tert-butylphenyl (d)], have been prepared in good yields from the sodium salts of the corresponding ligands and trans-Ni(PPh3)(2)(Ph)Cl, and the structure of complex 4a has been confirmed by X-ray crystallographic analysis. These neutral Ni(II) complexes were investigated as catalysts for the vinylic polymerization of norbornene. Using modified methylaluminoxane (MMAO) as a cocatalyst, these complexes display very high activities and produce great mass polymers. Catalyst activity of up to 4.2 x 10(7) g (mol Ni h)(-1) and the viscosity-average molecular weight of polymer of up to 9.2 x 10(5) g mol(-1) were observed. Catalyst activity, polymer yield, and polymer molecular weight can be controlled over a wide range by the variation of reaction parameters such as Al-Ni ratio, norbornene-catalyst ratio, monomer concentration, polymerization reaction temperature and time.

Self-immobilized catalysts for ethylene polymerization: neutral, single-component salicylaldiminato phenyl nickel(II) complexes bearing allyl substituents

A new family of self-immobilized ethylene polymerization catalysts, derived from neutral, single-component salicylaldiminato phenyl nickel complexes, is described.

Preparation and gas sensitivity of octa-n-butoxy-2,3-naphthalocyanine copper(II) Langmuir-Blodgett film

The formation process of monolayer of octa-n-butoxy-2,3-naphthalocyanine copper ( I), [CuNc(OBu)(8)], on water subphase was studied. Its multilayers were successifully deposited on the hydrophilic substrates by Z-type deposition mode using LB technique. Stable solid film with a limiting molecular area of 0.74 nm(2) and a collapse pressure of 55 mN/m were formed. The LB film structure was characterized by IR and electronic absorption spectra. Macrocycle of CuNc (OBu)(8) molecules have a face-to-face arrangement in the multilayers. These films have good sensitivities to vapor of alcohols, with the following sequence of sensitivities: i-PrOH>EtOH>MeOH. The response time and recovery time of the LB films to vapor of MeOH, EtOH and i-PrOH[volume fraction (1-5) X 10(-5)] were within 2 and 5 seconds respectively, while those of the LB films to ammonia(1 X 10(-4)) were 30-60 seconds and 4-5 minutes respectively.

The efficient syntheses of three novel bridging phenanthroline ligands and their binuclear ruthenium(II) complexes

Three bridging ligands (L) and their binuclear phenanthroline ruthenium(II) complexes {[Ru(1,10-phenanthroline)(2)](2)(L)}(PF6)(4) were synthesized and characterized by IR, H-1 NMR, and elemental analysis, where L are 1,8-adipoylamido-bis(1,10-phenanthroline-5-yl) (L-1), 1,11-azelaoylamidobis(1, 10-phenanthroline-5-yl) (L-2), and p-phthaloylamido-bis(1,10-phenanthroline-5-yl) (L-3).

Kinetics of electrocatalytic ascorbic acid at ultramicroelectrode modified by Eastman-AQ polymer containing tris(2,2-'-bipyridine) osmium(III/II) complexes as electron-transfer centers

The theoretical model[17] of an ultramicroelectrode modified with a redox species film is used as the diagnostic tool to characterize the catalytic oxidation of ascorbic acid at carbon fiber ultramicrodisk electrodes coated with an Eastman-AQ-Os(bpy)(3)(2+) film. The electrocatalytic behavior of ascorbic acid at the ultramicroelectrode modified by an Eastman-AQ polymer containing tris(2,2'-bipyridine) osmium(III/II) as mediators is described. In order to determine the five characteristic currents quantitatively, the radius of the ultramicroelectrode and the concentration of ascorbic acid are varied systematically. The kinetic zone diagram has been used to study the electrocatalytic system. This system with 0.5-2.75 mM ascorbic acid belongs to SR + E case, and the concentration profiles of the catalyst in the film are given in detail. Finally, optimizing the design of catalytic system is discussed.

A BINUCLEAR NICKEL(II) COMPLEX CONTAINING AN OXAMIDO-BRIDGE - SYNTHESIS, PROPERTIES AND X-RAY CRYSTAL-STRUCTURE OF [NI(OXAE)NI(PHEN)(2)](CLO4)(2)CENTER-DOT-3H2O

The binuclear complex [Ni(oxae)Ni(phen)2](ClO4)(2) . H2O (oxae=N,N'bis(2-aminoethyl) oxamido dianion, phen = 1, 10-phenanthroline) was prepared from the planar monomeric complex Ni(oxae) and characterized through analytical and spectroscopic measurements. The structure of [Ni(oxae)Ni(phen)(2)] (ClO4)2 . 3H(2)O was investigated by single-crystal X-ray analysis. The complex has an extended oxamido-bridged structure and consists of two nickel(II) ions, one of them in a square planar environment and another in a distorted octahedral environment. The Ni-Ni distance is 5.267 Angstrom.

Biosorption of copper(II) from aqueous solutions by green alga Cladophora fascicularis

Biosorption is an effective means of removal of heavy metals from wastewater. In this work the biosorption behavior of Cladophora fascicularis was investigated as a function of pH, amount of biosorbent, initial Cu2+ concentration, temperature, and co-existing ions. Adsorption equilibria were well described by Langmuir isotherm models. The enthalpy change for the biosorption process was found to be 6.86 kJ mol(-1) by use of the Langmuir constant b. The biosorption process was found to be rapid in the first 30 min. The presence of co-existing cations such as Na+, K+, Mg2+, and Ca2+ and anions such as chloride, nitrate, sulfate, and acetate did not significantly affect uptake of Cu2+ whereas EDTA substantially affected adsorption of the metal. When experiments were performed with different desorbents the results indicated that EDTA was an efficient desorbent for the recovery of Cu2+ from biomass. IR spectral analysis suggested amido or hydroxy, C=O, and C-O could combine strongly with Cu2+.

Biosorption of copper (II) and lead (II) from aqueous solutions by nonliving green algae Cladophora fascicularis: Equilibrium, kinetics and environmental effects

Biosorption of Cu2+ and Pb2+ by Cladophora fascicularis was investigated as a function of initial pH, initial heavy metal concentrations, temperature and other co-existing ions. Adsorption equilibriums were well described by Langmuir and Freundlich isotherm models. The maximum adsorption capacities were 1.61 mmol/ g for Cu2+ and 0.96 mmol/ g for Pb2+ at 298K and pH 5.0. The adsorption processes were endothermic and biosorption heats calculated by the Langmuir constant b were 39.0 and 29.6 kJ/ mol for Cu2+ and Pb2+, respectively. The biosorption kinetics followed the pseudo- second order model. No significant effect on the uptake of Cu2+ and Pb2+ by co-existing cations and anions was observed, except EDTA. Desorption experiments indicated that Na(2)EDTA was an efficient desorbent for the recovery of Cu2+ and Pb2+ from biomass. The results showed that Cladophora fascicularis was an effective and economical biosorbent material for the removal and recovery of heavy metal ions from wastewater.

Epoxidation of styrene with NaOCl and catalyzed by nickel(II) complexes

Epoxidation of styrene was catalyzed by some nickel(II) complexes, with NaOCl as the oxygen donor. The catalyst Ni(PA)(2). 2H(2)O has been found to be stable for the epoxidation of styrene. Some additives were introduced in the reaction to improve the "micro-environment" of the catalyst. Radical trap had little influence on styrene epoxidation. It was interesting to find that phase-transfer agent had negative influence on epoxidation in this biphase reaction. A possible mechanism of styrene epoxidation catalyzed by Ni(PA)(2). 2H(2)O has been proposed.

Synthesis, crystal structure, and magnetic properties of {[Cu(oxbe)]Mn(H2O)[Cu(oxbe)(DMF)]}(n)center dot nDMF center dot nH(2)O: From dissymmetrical mononuclear entities to a 3D heterometallic supramolecular coordination polymer

Self-assembly of the building block [Cu(oxbe)](-) with Mn(II) led to a novel coordination polymer {[Cu(oxbe)]Mn(H2O)(Cu(oxbe)(DMF)]}(n).nDMF.nH(2)O, where H(3)oxbe is a new dissymmetrical ligand N-benzoato-N'-(2-aminoethyl)-oxamido and DMF = dimethylformamide. The crystal forms in the triclinic system, space group P(1)over-bar, with a = 9.260(4) angstorm, b = 12.833(5) angstrom, c = 15.274(6) angstrom , alpha = 76.18(3)degrees, beta = 82.7(3)degrees, gamma = 82.31(3)degrees, and Z = 2. The crystal structure of the title complex reveals that the two-dimensional bimetallic layers are constructed of (CuMnII)-Mn-II-Cu-II chains linked together by carboxylate bridge and hydrogen bonds help to produce a novel three-dimensional channel-like structure. The magnetic susceptibility measurements (5-300 K) were analyzed by means of the Hamiltonian (H)over-cap = -2J(S)over-cap (Mn)((S)over-cap(Cu1) + (S)over-cap(Cu2)), leading to J = -17.4 cm(-1).